Heretofore, the primary market for slider bags has been consumers who purchase a package of empty slider bags and then fill the slider bags with products at home. However, with the increasing popularity of the slider bags, product manufacturers have become interested in packaging their food and non-food products in slider bags for sale to consumers. The slider bags are a great convenience to the consumer who purchases these product filled bags especially for products of the type where only a portion of the product is used at any given time. The product applications for which slider bags may be used are virtually unlimited.
Existing flexible packages with zipper assemblies suffer from problems such as not being able to retain aroma and freshness of food and other articles packaged inside them during transportation and storage. Hence, by the time the contents of the package reach the end user they are insipid. Furthermore, said zipper slider assemblies do not provide any adequate tamper-proof feature for informing the end user whether the package has been opened previously or not.
U.S. Pat. Nos. 5,435,864 and 5,425,825 disclose plastic bags having a re-closable plastic zipper and non re-closable peel seal. In U.S. Pat. No. 5,435,864, the peel seal is formed by co-extruding an adhesive onto a side strip adjacent to the interlocking zipper while, in U.S. Pat. No. 5,425,825 applying adhesive to the side strip forms the seal. Further, the barrier provided by a peel seal is permeable and is not strong enough for preventing undesired aroma, microorganisms, and moisture from entering into packages containing food items, thereby making the packaged items vulnerable to fast deterioration.
US Patent Application No. 2002/0021499A1 discloses a flexible re-closable package having a re-closable zipper construction openable and closable by a slider device, and a primary tamper evident structure disposed over the zipper for indicating whether access has been gained to the interior of the package. The package also has a second tamper evident structure consisting of a polymeric film or a peel seal, which is permeable. As a result, the structure has very limited barrier properties to prevent undesired aroma, microorganisms, and moisture from the atmosphere from entering the package. At the same time, the structure is not capable of retaining inside the package the desired aroma, microbe free air and gases like nitrogen that are filled in the package containing food items for keeping them fresh.
The further disadvantage of the above U.S. Pat. Nos. 5,435,864 & 5,425,825 and US Patent Application no. 2002/0021499A1 using a polymeric film extruded together with the zipper profile for providing tamper evident structure is that it limits the choice of material in case a structure having special properties such as capable of being holographed or printed is required for the package.
Further, flexible packaging with only two side gussets result in curved surfaces on the front and backside and therefore create a difficulty in stacking and also waste storage space.
In our co-pending application number 1260/mum/2003, we have described a slider zipper assembly with a diaphragm for a three-side gusset pouch that overcomes the aforementioned drawbacks. The application describes a flexible package with gussets on three sides and a slider zipper assembly that has a diaphragm of a metalized film that makes the package tamper proof and acts as a barrier against external environmental forces.
Although the diaphragm described in the said co-pending patent application has strong barrier properties and also provides a tamper evident feature, it is difficult for the end user to tear open the diaphragm to access the contents of the flexible package.
One of the conventional approaches used to overcome the aforementioned drawback involves perforating the diaphragm for making it easier to tear open. However, such a perforation compromises the barrier property of the diaphragm and hence, of the flexible package. Therefore, it is not fit in cases where the barrier is an essential requirement for storing the contents in the flexible package.
In our co-pending application number 718/mum/2003, we have described an improved slider zipper assembly with a diaphragm for flexible packages that overcomes the above-mentioned drawbacks and provides a zipper slider assembly with diaphragm having a score line for flexible packages that is more convenient for the user to tear open to access the contents of the package and at the same time possesses strong barrier properties for maintaining the desired aroma and freshness of food and other articles packaged inside the flexible package during transportation and storage till such time that they reach the end user. The means for scribing the score line include lasers and water jet technology.
Though the bags as described above offer excellent storage and storing properties, the end user or customer experiences some inconvenience in carrying such a bag that is filled. More particularly a completely filled flexible package as described above would require the end user to use both his hands to lift.
Conventional flexible packages usually come with moulded handles or handles punched in the package itself. An example of such a flexible package is the commonly available plastic/polyethene bags. The other types of bags with handles are usually jute or cloth bags. Flexible packages or bags with punched holes for handles as shown in EP 0524487 A1 and U.S. Pat. Nos. 6,533,711 and 6,053,635 waste the net storage space of the bag. In addition such flexible packages also permit wastage of material around the punched in handle.
U.S. Pat. No. 6,481,183 describes a bag made of a resilient material such as plastic that is made on a form, fill and seal machine. That is the bag is formed, filled with the specified contents and sealed at the same place. The bag as described cannot be used to fill contents at end users place. A lot of countries, including India, get the bags or flexible packages made elsewhere and do the filling and sealing at their own premises, to save on investment and production costs. The document further describes a stand up bag that has a vertical slider zipper along the centre or side of the bag and not covering the entire length. Accordingly the entire area of the bag cannot be used to fill. Further, the bag is unsuitable for solids, and in particular solids having width equal to or greater than the length of zipper. The bag as described also suffers from the following disadvantages in that it does not provide convenience in refilling after first use, in particular contents such as biscuits or sandwiches. The handle on the bag as shown in the document wastes storage space as well as material around the handle.
It is therefore an object of the invention to provide a flexible packaging with a slider zipper assembly, a diaphragm to provide the seal and tamper proof properties; a three side gusset to maximize package capacity and to aid in storage and that has a handle that provides convenience to the end user.